Factors relating to the formation and stabilization of collagen fibers are being investigated. In particular investigations are bein made on the subcellular localization of hydroxylationg and glycosylation reactions and the event of triplehelix formation. Studies are also being carried out on the heterogeneity of collagen in the skin and the process of conversion of procollagen to collagen. Comparative studies are in process concerning differences in cross-linkage distribution in hard and soft tissue collagens. Finally, the problem of assembly of collagen microfibrils from individual molecules is being examined, along with studies on the role of proteoglycans in the in vivo organization of fibers from fibrils.